Getting an error for "<- param"

Error

    No instance for (scotty-0.5.0:Web.Scotty.Action.Parsable t0)
      arising from a use of `param'
    The type variable `t0' is ambiguous
    Possible fix: add a type signature that fixes these type variable(s)
    Note: there are several potential instances:
      instance scotty-0.5.0:Web.Scotty.Action.Parsable ()
        -- Defined in `scotty-0.5.0:Web.Scotty.Action'
      instance scotty-0.5.0:Web.Scotty.Action.Parsable Bool
        -- Defined in `scotty-0.5.0:Web.Scotty.Action'
      instance scotty-0.5.0:Web.Scotty.Action.Parsable
                 Data.ByteString.Internal.ByteString
        -- Defined in `scotty-0.5.0:Web.Scotty.Action'
      ...plus 7 others
    In a stmt of a 'do' block: name <- param "name"
    In the second argument of `($)', namely
      `do { name <- param "name";
            html $ mconcat ["<p>/create/user/:userId/:name</p>"] }'
    In the expression:
      get "/create/user/:userId/:name"
      $ do { name <- param "name";
             html $ mconcat ["<p>/create/user/:userId/:name</p>"] }

myCode

{-# LANGUAGE OverloadedStrings #-}

module Controllers.Home
  (home
  , login
  , foo
  , createUser
  , foor
  ) where

import Web.Scotty (ScottyM, ActionM, get, html, param)
import Data.Monoid (mconcat)
import Views.Home (homeView)
import Views.Foor (foorView)


home :: ScottyM ()
home = get "/" homeView

login :: ScottyM()
login = get "/login" $ html "login"

foo :: ScottyM()
foo = get "/foo" $ html "Hello, this is foo!"

-- createUser :: ScottyM()
-- createUser =

createUser :: ActionM ()
createUser = get "/create/user/:userId/:name" $ do
  name <- param "name"
  html $ mconcat ["<p>/create/user/:userId/:name</p>"]



foor :: ScottyM()
foor = get "/404"  foorView